Multi-turn distributed active transformer power combiner

ABSTRACT

An apparatus includes a first primary coil, a second primary coil, and a secondary coil. The first and second primary coils each include a first, second, and third portion. The secondary coil includes a first and second portion in a first wafer layer, which are coupled together by a bridge in a second wafer layer. The second portion of the first primary coil is nested inside the first portion of the secondary coil in the first wafer layer. The second portion of the second primary coil is nested inside the second portion of the secondary coil in the first wafer layer. At least parts of the first and third portions of the first primary coil are adjacent the second portion of the secondary coil, and at least parts of the first and third portions of the second primary coil are adjacent the first portion of the secondary coil.

BACKGROUND

Distributed active transformers are used in power combining toefficiently increase signal power in radio frequency systems. For sometarget output signal powers, power amplifiers may require outputnetworks with high transformer ratios such as a one to threetransformation. However, the quality factor and coupling coefficients ofoutput transformer combiners degrade with the increased turn ratio andreduced coil size needed to provide such high transformer ratios,decreasing the efficiency.

SUMMARY

An apparatus includes a first primary coil, a second primary coil, and asecondary coil. The first and second primary coils each include a first,second, and third portion. The secondary coil includes a first andsecond portion in a first wafer layer, which are coupled together by abridge in a second wafer layer. The second portion of the first primarycoil is nested inside the first portion of the secondary coil in thefirst wafer layer. The second portion of the second primary coil isnested inside the second portion of the secondary coil in the firstwafer layer. At least parts of the first and third portions of the firstprimary coil are adjacent the second portion of the secondary coil, andat least parts of the first and third portions of the second primarycoil are adjacent the first portion of the secondary coil.

In some implementations, the first and third portions of the firstprimary coil are in the first wafer layer, and the parts of the firstand third portions of the first primary coil are nested outside thesecond portion of the secondary coil. The first and third portions ofthe second primary coil are in the first wafer layer, and the parts ofthe first and third portions of the second primary coil are nestedoutside the first portion of the secondary coil. The first and secondportions of the second primary coil are coupled together in the firstwafer layer by a first joiner, and the second and third portions of thesecond primary coil are coupled together in the first wafer layer by asecond joiner, in some implementations.

The first and second portions of the first primary coil are coupledtogether by a third joiner in the second wafer layer, and the second andthird portions of the first primary coil are coupled together by afourth joiner in the second wafer layer, in some implementations. Inother implementations, the first and second portions of the firstprimary coil are coupled together by a third joiner in a third waferlayer and the second and third portions of the first primary coil arecoupled together by a fourth joiner in the third wafer layer. The secondwafer layer is above the first wafer layer, and the third wafer layer isbelow the first wafer layer, in some implementations.

The apparatus can further comprise a first lead coupled to the firstportion of the secondary coil and a second lead coupled to the secondportion of the secondary coil. The first and second leads provide adifferential output signal. In some implementations, the first andsecond leads are in the second wafer layer. In some implementations, thefirst and third portions of the first primary coil receive a firstdifferential input signal, and the first and third portions of thesecond primary coil receive a second differential input signal.

BRIEF DESCRIPTION OF THE DRAWINGS

For a detailed description of various examples, reference will now bemade to the accompanying drawings in which:

FIGS. 1A-D illustrate different perspectives of a multi-turn distributedactive transformer power combiner.

FIG. 2 shows a diagram of current flow through the multi-turndistributed active transformer power combiner shown in FIG. 1A.

FIGS. 3A-E illustrate different perspectives of another multi-turndistributed active transformer power combiner.

FIGS. 4A-C illustrate different perspectives of another multi-turndistributed active transformer power combiner with a two-to-two turnratio.

FIGS. 5A-C illustrate different perspectives of a multi-turn distributedactive transformer power combiner with a three-to-two turn ratio.

FIGS. 6A-C illustrate different perspectives of a multi-turn distributedactive transformer power combiner with a three-to-three turn ratio.

DETAILED DESCRIPTION

The same reference number is used in the drawings for the same orsimilar (either by function and/or structure) features.

The described multi-turn distributed active transformer (DAT) powercombiners include first and second primary coils having three portionseach and a secondary coil with two portions. The first and secondportions of the secondary coil are in a first wafer layer and coupledtogether by a bridge in a second wafer layer adjacent the first waferlayer. The second portions of the first and second primary coils arenested inside the first and second portions of the secondary coil in thefirst wafer layer. At least parts of the first and third portions of thefirst primary coil are adjacent the second portion of the secondarycoil, and at least parts of the first and third portions of the secondprimary coil are adjacent the first portion of the secondary coil.

FIGS. 1A-D illustrate different perspectives of a multi-turn DAT powercombiner 100. FIG. 1A illustrates an overhead view 100A of the powercombiner 100, which includes a first primary coil 120, a second primarycoil 130, and a secondary coil 140 in a single layer. The primary coils120 and 130 sandwich the secondary coil 140, such that primary coils 120and 130 and the secondary coil 140 are sidewall coupled together. Aground ring 190 isolates the DAT power combiner 100 from other circuitson the semiconductor wafer. The secondary coil 140 is described furtherwith respect to FIG. 1B and includes a first portion 140A and a secondportion 140B having a same width. The first primary coil 120 isdescribed further with respect to FIG. 1C and includes three portionshaving a same width: a first portion 120A, a second portion 120B, and athird portion 120C. Similarly, the second primary coil 130 is describedfurther with respect to FIG. 1D and includes three portions having asame width: a first portion 130A, a second portion 130B, and a thirdportion 130C.

FIG. 1B shows a perspective view 100B of the secondary coil 140. Thefirst and second portions 140A-B of the secondary coil 140 form halfcircles in a first layer 160 of the DAT power combiner 100 and areconnected together by bridge 145 in a different layer 170 of the DATpower combiner 100. A first via connects the first portion 140A in layer160 to the bridge 145 in layer 170, and a second via connects the secondportion 140B in layer 160 to the bridge 145 in layer 170. A first lead155A in the layer 170 is coupled to the first portion 140A in layer 160by a via and provides the positive output signal OUTP 150A of thedifferential output signal OUT 150. A second lead 155B in the layer 170is coupled to the second portion 140B in layer 160 by a via and providesthe negative output signal OUTM 150B of OUT 150. In this example, thelayer 170 including the bridge 145 and leads 155A-B is above the layer160 including the secondary coil 140, but in other implementations, thelayer 170 is below the layer 160.

FIG. 1C shows a perspective view 100C of the first primary coil 120. Thefirst portion 120A of the first primary coil 120 receives a positiveinput INP 105A of a first differential input signal IN 105 and forms aquarter circle around the outside of the first portion 140A of thesecondary coil 140 in layer 160. The first portion 120A and the secondportion 120B of the first primary coil 120 in layer 160 are coupledtogether by a first S-shaped joiner 125A in a different layer 180 of theDAT power combiner 100. The layer 180 is different from the layer 170shown in FIG. 1B. A first via connects the first portion 120A in layer160 to the first joiner 125A in layer 180, and a second via connects thesecond portion 120B in layer 160 to the first joiner 125 in layer 180.The second portion 120B forms a half circle along the inside of thesecond portion 140B of the secondary coil 140 in layer 160.

The second portion 120B and the third portion 120C of the first primarycoil 120 in layer 160 are coupled together by a second S-shaped joiner125B in the layer 180. A first via connects the second portion 120B inlayer 160 to the second joiner 125B in layer 180, and a second viaconnects the third portion 120C in layer 160 to the second joiner 125Bin layer 180. The third portion 120C of the first primary coil 120 formsa quarter circle around the outside of the first portion 140A of thesecondary coil 140 in layer 160 and receives a negative input INM 105Bof IN 105. In this example, the layer 180 including the first and secondjoiners 125A-B is placed below the layer 160 including the first primarycoil 120, but in other implementations, the layer 180 is placed in alayer above the layer 160 such as in implementations in which the layer170 including the bridge 145 and leads 155A-B is placed below the layer160.

FIG. 1D shows a perspective view of the second primary coil 130. Thefirst portion 130A of the second primary coil 130 receives a positiveinput INP 110A of a second differential input signal IN 110 and forms aquarter circle around the outside of the second portion 140B of thesecondary coil 140 in layer 160. The first portion 130A and the secondportion 130B of the second primary coil 130 are coupled together by afirst S-shaped joiner 135A in the same layer 160. The second portion130B forms a half circle along the inside of the first portion 140A ofthe secondary coil 140. The second portion 130B and the third portion130C of the second primary coil 130 are coupled together by a secondS-shaped joiner 135B in the same layer 160.

The third portion 130C of the second primary coil 130 forms a quartercircle around the outside of the second portion 140B of the secondarycoil 140 in layer 160 and receives a negative input INM 110B of IN 110.In this example, the first and second joiners 125A-B are placed in adifferent layer 180, and the first and second joiners 135A-B are placedin the same layer 160. In other implementations, the first and secondjoiners 125A-B are placed in the same layer 160, and the first andsecond joiners 135A-B are placed in the different layer 180. In someimplementations, the layer 170 and the layer 180 are the same layer,such that the bridge 145, the leads 155A-B, and the joiners 125A-B and135A-B are in a same layer.

FIG. 2 shows a diagram 200 of current flow through the multi-turn DATpower combiner 100 shown in FIG. 1A. The input signal IN 105 followspath 210 through the first primary coil 120, and the input signal IN 110follows path 220 through the second primary coil 130. In path 210, thecurrent directions between the outer, first portion 120A of the firstprimary coil 120 to the inner, second portion 120B of the first primarycoil 120 are the same, and the current directions between the inner,second portion 120B to the outer, third portion 120C of the firstprimary coil 120 are the same. The same current direction throughoutpath 210 increases the mutual inductance of the first primary coil 120.

Similarly in path 220, the current directions between the outer, firstportion 130A of the second primary coil 130 to the inner, second portion130B of the second primary coil 130 are the same, and the currentdirections between the inner, second portion 130B to the outer, thirdportion 130C of the second primary coil 130 are the same. The samecurrent direction throughout path 220 increases the mutual inductance ofthe second primary coil 130. In addition, the same widths of theportions 120A-C of the first primary coil 120 cause the input signal IN105 to have a same signal strength and phase throughout the portions120A-C. The same widths of the portions 130A-C of the second primarycoil 130 cause the input signal IN 110 to have a same signal strengthand phase throughout the portions 130A-C.

FIG. 3A-E illustrate different perspectives of another multi-turn DATpower combiner 300. FIG. 3A illustrates an overhead view 300A of thepower combiner 300, which includes a first primary coil 320, a secondprimary coil 330, and a secondary coil 340. The primary coils 320 and330 are placed underneath and inside the secondary coil 340, such thatprimary coils 320 and 330 and the secondary coil 340 are coupledtogether both by sidewall coupling and broadside coupling. A ground ring390 isolates the DAT power combiner 300 from other circuits on thesemiconductor wafer. The secondary coil 340 is described further withrespect to FIG. 3B and includes three portions having a same width: afirst portion 340A in a first layer, a second portion 340B in a secondlayer, and a third portion 340C in the first layer.

The first primary coil 320 is described further with respect to FIG. 3Cand includes two portions having a same width: a first portion 320A in athird layer and a second portion 320B in the first layer. Similarly, thesecond primary coil 330 is described further with respect to FIG. 3D andincludes two portions having a same width: a first portion 330A in thethird layer and a second portion 330B in the first layer. The secondportion 330B of the second primary coil 330 is coupled to a first supplyvoltage Vsupply 360, and the second portion 320B of the first primarycoil 320 is coupled to receive a second supply voltage Vsupply 365. Insome implementations, the supply voltages Vsupply 360 and 365 are thesame.

FIG. 3B shows a perspective view 300B of the secondary coil 340. Thefirst portion 340A of the secondary coil 340 in layer 370 is coupled toa lead 355A in layer 375 by a via 345A. The lead 355A provides thepositive output signal OUTP 350A of the differential output signal 350.The first portion 340A in layer 370 is coupled to the second portion340B of the secondary coil 340 in layer 375 by a via 345B. The secondportion 340B is coupled to the third portion 340C in layer 370 by a via345C. The third portion 340C is coupled to a lead 355B in layer 375 by avia 345D. The lead 355B provides the negative output signal OUTM 350B ofOUT 350. In this example, the layer 375 including the second portion340B and leads 355A-B is placed above the layer 370 including the firstportion 340A and the third portion 340C, but in other implementations,the layer 375 is placed below the layer 370.

FIG. 3C shows a perspective view 300C of the first primary coil 320. Thefirst portion 320A of the first primary coil 320 receives a positiveinput INP 305A of a first differential input signal IN 305 and ispositioned in layer 380 below the third portion 340C of the secondarycoil 340 in the layer 370. The shape of the first portion 320A of thefirst primary coil 320 is arranged such that the via 325A couples thefirst portion 320A to the second portion 320B of the first primary coil320 in layer 370.

The second portion 320B of the first primary coil 320 nests on theinside the first portion 340A of the secondary coil 340 in layer 370.The shape of the third portion 320C of the first primary coil 320 inlayer 380 is arranged such that the via 325B couples the second portion320B in layer 370 to the third portion 320C in layer 380. The thirdportion 320C receives a negative input INM 305B of the first inputsignal IN 305. The layer 380 is placed below the layer 370 in thisexample, but in other implementations, the layer 380 is placed above thelayer 370.

FIG. 3D shows a perspective view 300D of the second primary coil 330.The first portion 330A of the second primary coil 330 receives apositive input INP 310A of a second differential input signal IN 310 andis positioned in layer 380 below the first portion 340A of the secondarycoil 340 in the layer 370. The shape of the first portion 330A of thesecond primary coil 320 is arranged such that the via 335A couples thefirst portion 330A to the second portion 330B of the second primary coil330 in layer 370.

The second portion 330B of the second primary coil 330 nests on theinside the second portion 340B of the secondary coil 340 in layer 370.The shape of the third portion 330C of the second primary coil 330 inlayer 380 is arranged such that the via 335B couples the second portion330B in layer 370 to the third portion 330C in layer 380. The thirdportion 330C receives a negative input INM 310B of the second inputsignal IN 310. The layer 380 is placed below the layer 370 in thisexample, but in other implementations, the layer 380 is placed above thelayer 370.

In this example, the first portion 320A and the third portion 320C ofthe first primary coil 320 and the first portion 330A and the thirdportion 330C of the second primary coil 330 are placed in a layer 380that is different from the layer 375 including the second portion 340Bof the secondary coil 340. In other implementations, the first portion320A and the third portion 320C of the first primary coil 320 and thefirst portion 330A and the third portion 330C of the second primary coil330 are placed in the same layer 375 including the second portion 340Bof the secondary coil 340.

FIG. 3E shows a perspective view 300E of the multi-turn DAT powercombiner 300. The first portion 320A and the third portion 320C of thefirst primary coil 320 and the first portion 330A and the third portion330C of the second primary coil 330 are placed in a layer 380 beneaththe layer 370, which includes the second portion 320B of the firstprimary coil 320 nested inside the first portion 340A of the secondarycoil 340 and the second portion 330B of the second primary coil 330nested inside the third portion 340C of the secondary coil. The layer375 above the layer 370 includes second portion 340B of the secondarycoil 340 and the leads 355A-B.

FIGS. 4A-C illustrate different perspectives of another multi-turndistributed active transformer power combiner 400 with a two-to-two turnratio. FIG. 4A shows an overhead view 400A of the power combiner 400,which includes a first primary coil 420, a second primary coil 430, anda secondary coil 440 in a single layer. The primary coils 420 and 430are interleaved with the secondary coil 440 such that the primary coils420 and 430 and the secondary coil 440 are sidewall coupled together.The primary coils 420 and 430 are described further herein with respectto FIG. 4B and each include three portions having a same width. Thesecondary coil 440 is described further herein with respect to FIG. 4Cand includes three portions having a same width.

FIG. 4B shows an overhead view 400B of the primary coils 420 and 430.The first primary coil 420 includes a first portion 420A, a secondportion 420B, and a third portion 420C. The second primary coil 430includes a first portion 430A, a second portion 430B, and a thirdportion 430C. The first portion 420A of the first primary coil 420receives a positive input INP 405A of a first differential input signalIN 405 and forms a quarter circle in a first layer of the DAT powercombiner 400. The first portion 420A and the second portion 420B of thefirst primary coil 420 are coupled together by a first joiner 425A thatmay be in the same or a different layer of the DAT power combiner 400.The different layer may be above or below the layer of the DAT powercombiner 400 that includes the first and second portions 420A and 420B,respectively.

The second portion 420B forms a half circle along the inside of thesecondary coil 440 in the same first layer as the first portion 420A.The second portion 420B and the third portion 420C of the first primarycoil 420 in the first layer are coupled together by a second joiner 425Bin the same or the different layer of the DAT power combiner 400. Thesecond joiner 425B is in a same layer as the first joiner 425A. Thethird portion 420C of the first primary coil 420 forms a quarter circleand receives a negative input INM 405B of IN 405.

The first portion 430A of the second primary coil 430 receives apositive input INP 410A of a second differential input signal IN 410 andforms a quarter circle in the first layer of DAT power combiner 400. Thefirst portion 430A and the second portion 430B of the second primarycoil 430 are coupled together by a first joiner 435A in the same layeror a different, second layer of the DAT power combiner 400 as the firstand second portions 430A and 430B, respectively. In implementations inwhich the joiners 425A-B are in the same, first layer as the first,second, and third portions 420A-C of the first primary coil 420 and thefirst and second portions 430A-B of the second primary coil 430, thejoiner 435A is in the second layer. In implementations in which thejoiners 425A-B are in the different, second layer of the DAT powercombiner 400 as the first, second, and third portions 420A-C of thefirst primary coil 420 and the first and second portions 430A-B of thesecond primary coil 430, the joiner 435A can be in the same, first layeras the first, second, and third portions 420A-C of the first primarycoil 420 and the first and second portions 430A-B of the second primarycoil 430 or a different, third layer from both the first layer and thedifferent, second layer.

The second portion 430B of the second primary coil 430 forms a halfcircle along the inside of the secondary coil 440. The second portion430B and the third portion 430C of the second primary coil 430 arecoupled together by a second joiner 435B in the same layer as the firstjoiner 435A. The third portion 430C of the second primary coil 430 formsa quarter circle and receives a negative input INM 410B of IN 410.

FIG. 4C shows an overhead view 400C of the secondary coil 440. A firstlead 455A in a different layer from the first layer is coupled to thefirst portion 440A of the secondary coil 440 by a via and provides thepositive output signal OUTP 450A of the differential output signal OUT450. A second lead 455B in the different layer is coupled to the thirdportion 440C of the secondary coil 440 by a via and provides thenegative output signal OUTM 450B of OUT 450. The first portion 440A ofthe secondary coil 440 forms a half circle in the first layer of the DATpower combiner 400.

The second portion 440B of the secondary coil 440 forms a circle insidethe half circle of the first portion 440A in the first layer. The firstand second portions 440A and 440B of the secondary coil 440 are coupledtogether by a first joiner 445A, which may be in the same or thedifferent second or third layers. The third portion 440C of thesecondary coil 440 forms a half circle on the outside of the innerportion 440B and is coupled to the second lead 455B.

FIGS. 5A-C illustrate different perspectives of a multi-turn distributedactive transformer power combiner 500 with a three-to-two turn ratio.FIG. 5A shows an overhead view 500A of the power combiner 500, whichincludes a first primary coil 520, a second primary coil 530, and asecondary coil 540 in a single layer. The primary coils 520 and 530 areinterleaved with the secondary coil 540 such that the primary coils 520and 530 and the secondary coil 540 are sidewall coupled together. Theprimary coils 520 and 530 are described further herein with respect toFIG. 5B and each include five portions having a same width. Thesecondary coil 540 is described further herein with respect to FIG. 5Cand includes three portions having a same width.

FIG. 5B shows an overhead view 500B of the primary coils 520 and 530.The first primary coil 520 includes a first portion 520A, a secondportion 520B, a third portion 520C, a fourth portion 520D, and a fifthportion 520E in the first layer. The second primary coil 530 includes afirst portion 530A, a second portion 530B, a third portion 530C, afourth portion 530D, and a fifth portion 530E in the first layer. Thefirst portion 520A of the first primary coil 520 receives a positiveinput INP 505A of a first differential input signal IN 505 and forms aquarter circle in a first layer of the DAT power combiner 500. The firstportion 520A and the second portion 520B of the first primary coil 520are coupled together by a first joiner 525A that may be in the same or adifferent layer of the DAT power combiner 500. The different layer maybe above or below the layer of the DAT power combiner 500 that includesthe first and second portions 520A and 520B, respectively.

The second portion 520B forms a quarter circle in the same first layeras the first portion 520A. The second portion 520B and the third portion520C of the first primary coil 520 in the first layer are coupledtogether by a second joiner 525B in the same or the different layer ofthe DAT power combiner 500. The second joiner 525B is in a same layer asthe first joiner 525A. The third portion 520C of the first primary coil520 forms a half circle and is coupled to the fourth portion 520D by athird joiner 525C in the same layer as the first and second joiners 525Aand 525B. The fourth portion 520D forms a quarter circle on the insideof the first portion 520A and is coupled to the fifth portion 520E by afourth joiner 525D in the same layer as the first, second, and thirdjoiners 525A-C. The fifth portion 520E forms a quarter circle on theoutside of the second portion 520B and receives a negative input INM505B of the first differential input signal IN 505.

The first portion 530A of the second primary coil 530 receives apositive input INP 510A of a second differential input signal IN 510 andforms a quarter circle in the first layer of DAT power combiner 500. Thefirst portion 530A and the second portion 530B of the second primarycoil 530 are coupled together by a first joiner 535A in the same layeror a different, third layer of the DAT power combiner 500 as the firstand second portions 530A and 530B, respectively. In implementations inwhich the joiners 525 are in the same, first layer as the first primarycoil 520 and the first and second portions 530A-B of the second primarycoil 530, the joiner 535A is in the different layer. In implementationsin which the joiners 525 are in the different, second layer as the firstprimary coil 520 and the first and second portions 530A-B of the secondprimary coil 530, the joiner 535A can be in the same, first layer as thefirst primary coil 520 and the first and second portions 530A-B of thesecond primary coil 530 or a different, third layer from both the firstlayer and the different, second layer.

The second portion 530B of the second primary coil 530 forms a quartercircle along the inside of the secondary coil 540. The second portion530B and the third portion 530C of the second primary coil 530 arecoupled together by a second joiner 535B in the same layer as the firstjoiner 535A. The third portion 530C of the second primary coil 530 formsa half circle and is coupled to the fourth portion 530D by a thirdjoiner 535C in the same layer as the first and second joiners 535A and535B. The fourth portion 530D forms a quarter circle on the inside ofthe first portion 530A and is coupled to the fifth portion 530E by afourth joiner 535D in the same layer as the first, second, and thirdjoiners 535A-C. The fifth portion 530E forms a quarter circle on theoutside of the second portion 530B, and receives a negative input INM510B of the first differential input signal IN 510.

FIG. 5C shows an overhead view 500C of the secondary coil 540. A firstlead 555A in a different layer from the first layer is coupled to thefirst portion 540A of the secondary coil 540 by a via and provides thepositive output signal OUTP 550A of the differential output signal OUT550. A second lead 555B in the different layer is coupled to the thirdportion 540C of the secondary coil 540 by a via and provides thenegative output signal OUTM 550B of OUT 550. The first portion 540A ofthe secondary coil 540 forms a half circle in the first layer of the DATpower combiner 500.

The second portion 540B of the secondary coil 540 forms a circle insidethe half circle of the first portion 540A in the first layer. The firstand second portions 540A and 540B of the secondary coil 540 are coupledtogether by a first joiner 545A, which may be in the same or thedifferent second or third layers. The third portion 540C of thesecondary coil 540 forms a half circle on the outside of the innerportion 540B and is coupled to the second lead 555B.

FIGS. 6A-C illustrate different perspectives of a multi-turn distributedactive transformer power combiner 600 with a three-to-three turn ratio.FIG. 6A shows an overhead view 600A of the power combiner 600, whichincludes a first primary coil 620, a second primary coil 630, and asecondary coil 640 in a single layer. The primary coils 620 and 630 areinterleaved with the secondary coil 640 such that the primary coils 620and 630 and the secondary coil 640 are sidewall coupled together. Theprimary coils 620 and 630 are described further herein with respect toFIG. 6B and each include five portions having a same width. Thesecondary coil 640 is described further herein with respect to FIG. 6Cand includes five portions having a same width.

FIG. 6B shows an overhead view 600B of the primary coils 620 and 630.The first primary coil 620 includes a first portion 620A, a secondportion 620B, a third portion 620C, a fourth portion 620D, and a fifthportion 620E in the first layer. The second primary coil 630 includes afirst portion 630A, a second portion 630B, a third portion 630C, afourth portion 630D, and a fifth portion 630E in the first layer. Thefirst portion 620A of the first primary coil 620 receives a positiveinput INP 605A of a first differential input signal IN 605 and forms aquarter circle in a first layer of the DAT power combiner 600. The firstportion 620A and the second portion 620B of the first primary coil 620are coupled together by a first joiner 625A that may be in the same or adifferent layer of the DAT power combiner 600. The different layer maybe above or below the layer of the DAT power combiner 600 that includesthe first and second portions 620A and 620B, respectively.

The second portion 620B forms a quarter circle in the same first layeras the first portion 620A. The second portion 620B and the third portion620C of the first primary coil 620 in the first layer are coupledtogether by a second joiner 625B in the same or the different layer ofthe DAT power combiner 600. The second joiner 625B is in a same layer asthe first joiner 625A. The third portion 620C of the first primary coil620 forms a half circle and is coupled to the fourth portion 620D by athird joiner 625C in the same layer as the first and second joiners 625Aand 625B. The fourth portion 620D forms a quarter circle on the insideof the first portion 620A and is coupled to the fifth portion 620E by afourth joiner 625D in the same layer as the first, second, and thirdjoiners 625A-C. The fifth portion 620E forms a quarter circle on theoutside of the second portion 620B, and receives a negative input INM605B of the first differential input signal IN 605.

The first portion 630A of the second primary coil 630 receives apositive input INP 610A of a second differential input signal IN 610 andforms a quarter circle in the first layer of DAT power combiner 600. Thefirst portion 630A and the second portion 630B of the second primarycoil 630 are coupled together by a first joiner 635A in the same layeror a different, third layer of the DAT power combiner 600 as the firstand second portions 630A and 630B, respectively. In implementations inwhich the joiners 625 are in the same, first layer as the first primarycoil 620 and the first and second portions 630A-B of the second primarycoil 630, the joiner 635A is in the different layer. In implementationsin which the joiners 625 are in the different, second layer as the firstprimary coil 620 and the first and second portions 630A-B of the secondprimary coil 630, the joiner 635A can be in the same, first layer as thefirst primary coil 620 and the first and second portions 630A-B of thesecond primary coil 630 or a different, third layer from both the firstlayer and the different, second layer.

The second portion 630B of the second primary coil 630 forms a quartercircle along the inside of the secondary coil 640. The second portion630B and the third portion 630C of the second primary coil 630 arecoupled together by a second joiner 635B in the same layer as the firstjoiner 635A. The third portion 630C of the second primary coil 630 formsa half circle and is coupled to the fourth portion 630D by a thirdjoiner 635C in the same layer as the first and second joiners 635A and635B. The fourth portion 630D forms a quarter circle on the inside ofthe first portion 630A and is coupled to the fifth portion 630E by afourth joiner 635D in the same layer as the first, second, and thirdjoiners 635A-C. The fifth portion 630E forms a quarter circle on theoutside of the second portion 630B, and receives a negative input INM610B of the first differential input signal IN 610.

FIG. 6C shows an overhead view 600C of the secondary coil 640. A firstlead 655A in a different layer from the first layer is coupled to thefirst portion 640A of the secondary coil 640 by a via and provides thepositive output signal OUTP 650A of the differential output signal OUT650. A second lead 655B in the different layer is coupled to the fifthportion 640E of the secondary coil 640 by a via and provides thenegative output signal OUTM 650B of OUT 650. The first portion 640A ofthe secondary coil 640 forms a half circle in the first layer of the DATpower combiner 600.

The second portion 640B of the secondary coil 640 forms a smaller halfcircle opposite the half circle of the first portion 640A in the firstlayer. The first and second portions 640A and 640B of the secondary coil640 are coupled together by a first joiner 645A, which may be in thesame first layer or the different second or third layers. Inimplementations in which the joiners 625 or 635 are in the first layer,the joiner 645A is in the different second or third layers. Inimplementations in which the joiners 625 and 635 are in the differentsecond or third layers, the joiner 645A is in the same first layer.

The third portion 640C of the secondary coil 640 forms a circle insidethe half circles of portions 640A and 640B, and is coupled to theportion 640B by a second joiner 645B in the same layer as the firstjoiner 645A. The fourth portion 640D of the secondary coil 640 forms ahalf circle between the third portion 640C and the first portion 640Aand is coupled to the third portion 640C by a third joiner 645C in thesame layer as joiners 645A-B. The fifth portion 640E of the secondarycoil 640 forms a half circle outside the second portion 640B and iscoupled to the fourth portion 640D by a fourth joiner 645D in the samelayer as joiners 645A-C. The fifth portion 640E is further coupled tothe second lead 655B.

The two-to-one, two-to-two, three-to-two, and three-to-three turn ratiosare shown herein to illustrate the extension of the principled describedherein to a variety of turn ratios and layer configurations. Other turnratios and layer configurations are possible within the scope of thisdescription.

In this description, the term “couple” may cover connections,communications, or signal paths that enable a functional relationshipconsistent with this description. For example, if device A generates asignal to control device B to perform an action: (a) in a first example,device A is coupled to device B by direct connection; or (b) in a secondexample, device A is coupled to device B through intervening component Cif intervening component C does not alter the functional relationshipbetween device A and device B, such that device B is controlled bydevice A via the control signal generated by device A.

A device that is “configured to” perform a task or function may beconfigured (e.g., programmed and/or hardwired) at a time ofmanufacturing by a manufacturer to perform the function and/or may beconfigurable (or reconfigurable) by a user after manufacturing toperform the function and/or other additional or alternative functions.The configuring may be through firmware and/or software programming ofthe device, through a construction and/or layout of hardware componentsand interconnections of the device, or a combination thereof.

As used herein, the terms “terminal”, “node”, “interconnection”, “pin”and “lead” are used interchangeably. Unless specifically stated to thecontrary, these terms are generally used to mean an interconnectionbetween or a terminus of a device element, a circuit element, anintegrated circuit, a device or other electronics or semiconductorcomponent.

A circuit or device that is described herein as including certaincomponents may instead be adapted to be coupled to those components toform the described circuitry or device. For example, a structuredescribed as including one or more semiconductor elements (such astransistors), one or more passive elements (such as resistors,capacitors, and/or inductors), and/or one or more sources (such asvoltage and/or current sources) may instead include only thesemiconductor elements within a single physical device (e.g., asemiconductor die and/or integrated circuit (IC) package) and may beadapted to be coupled to at least some of the passive elements and/orthe sources to form the described structure either at a time ofmanufacture or after a time of manufacture, for example, by an end-userand/or a third-party.

Uses of the phrase “ground” in the foregoing description include achassis ground, an Earth ground, a floating ground, a virtual ground, adigital ground, a common ground, and/or any other form of groundconnection applicable to, or suitable for, the teachings of thisdescription. In this description, unless otherwise stated, “about,”“approximately” or “substantially” preceding a parameter means beingwithin +/−10 percent of that parameter.

Modifications are possible in the described embodiments, and otherembodiments are possible, within the scope of the claims.

What is claimed is:
 1. An apparatus, comprising: a first primary coilcomprising a first portion, a second portion, and a third portion; asecond primary coil comprising a first portion, a second portion, and athird portion; and a secondary coil comprising a first portion and asecond portion in a first wafer layer, wherein the first and secondportions are coupled together by a bridge in a second wafer layer,wherein: the second portion of the first primary coil is in the firstwafer layer and nested inside the first portion of the secondary coil;the second portion of the second primary coil is in the first waferlayer and nested inside the second portion of the secondary coil; atleast parts of the first and third portions of the first primary coilare adjacent the second portion of the secondary coil; and at leastparts of the first and third portions of the second primary coil areadjacent the first portion of the secondary coil.
 2. The apparatus ofclaim 1, wherein: the first and third portions of the first primary coilare in the first wafer layer; the parts of the first and third portionsof the first primary coil are nested outside the second portion of thesecondary coil; the first and third portions of the second primary coilare in the first wafer layer; and the parts of the first and thirdportions of the second primary coil are nested outside the first portionof the secondary coil.
 3. The apparatus of claim 2, wherein the firstand second portions of the second primary coil are coupled together inthe first wafer layer by a first joiner and the second and thirdportions of the second primary coil are coupled together in the firstwafer layer by a second joiner.
 4. The apparatus of claim 3, wherein thefirst and second portions of the first primary coil are coupled togetherby a third joiner in the second wafer layer and the second and thirdportions of the first primary coil are coupled together by a fourthjoiner in the second wafer layer.
 5. The apparatus of claim 3, whereinthe first and second portions of the first primary coil are coupledtogether by a third joiner in a third wafer layer and the second andthird portions of the first primary coil are coupled together by afourth joiner in the third wafer layer.
 6. The apparatus of claim 5,wherein the second wafer layer is above the first wafer layer, andwherein the third wafer layer is below the first wafer layer.
 7. Theapparatus of claim 1, further comprising: a first lead coupled to thefirst portion of the secondary coil; and a second lead coupled to thesecond portion of the secondary coil, wherein the first and second leadsare configured to provide a differential output signal.
 8. The apparatusof claim 7, wherein the first and second leads are in the second waferlayer.
 9. The apparatus of claim 1, wherein the first and third portionsof the first primary coil are configured to receive a first differentialinput signal, and wherein the first and third portions of the secondprimary coil are configured to receive a second differential inputsignal.
 10. A distributed active transformer (DAT), comprising: a firstprimary coil comprising a first portion, a second portion, and a thirdportion; a second primary coil comprising a first portion, a secondportion, and a third portion; and a secondary coil adjacent the firstand second primary coils and comprising a first portion and a secondportion in a first wafer layer, wherein: the first and second portionsof the secondary coil are coupled together by a bridge in a second waferlayer adjacent the first wafer layer; the second portion of the firstprimary coil is in the first wafer layer and inside the first portion ofthe secondary coil; and the second portion of the second primary coil isin the first wafer layer and inside the second portion of the secondarycoil.
 11. The DAT of claim 10, wherein: the first and third portions ofthe first primary coil are in a third wafer layer; the first and thirdportions of the second primary coil are in the third wafer layer; andthe third wafer layer is adjacent the first wafer layer.
 12. The DAT ofclaim 11, wherein: the first portion of the first primary coil in thethird wafer layer is coupled to the second portion of the first primarycoil in the first wafer layer by a first via; the second portion of thefirst primary coil in the first wafer layer is coupled to the thirdportion of the first primary coil in the third wafer layer by a secondvia; the first portion of the second primary coil in the third waferlayer is coupled to the second portion of the second primary coil in thefirst wafer layer by a third via; and the second portion of the secondprimary coil in the first wafer layer is coupled to the third portion ofthe second primary coil in the third wafer layer by a fourth via. 13.The DAT of claim 12, wherein the second wafer layer is above the firstwafer layer, and wherein the third wafer layer is below the first waferlayer.
 14. The DAT of claim 10, further comprising: a first lead in thesecond wafer layer and coupled to the first portion of the secondarycoil by a first via; and a second lead in the second wafer layer andcoupled to the second portion of the secondary coil by a second via,wherein the first and second leads are configured to provide adifferential output signal.
 15. The DAT of claim 10, further comprising:a first supply voltage line coupled to the second portion of the firstprimary coil; and a second supply voltage line coupled to the secondportion of the second primary coil.
 16. A system, comprising: a firstprimary coil comprising a first portion, a second portion, and a thirdportion, wherein the second portion of the first primary coil is in afirst wafer layer; a second primary coil comprising a first portion, asecond portion, and a third portion, wherein the second portion of thesecond primary coil is in the first wafer layer; and a secondary coiladjacent the first and second primary coils and comprising a firstportion and a second portion in the first wafer layer, wherein the firstand second portions of the secondary coil are coupled together by abridge in a second wafer layer adjacent the first wafer layer.
 17. Thesystem of claim 16, wherein the first and third portions of the firstprimary coil and the first and third portions of the second primary coilare in the first wafer layer.
 18. The system of claim 17, wherein: thesecond portion of the first primary coil is nested inside the firstportion of the secondary coil; at least parts of the first and thirdportions of the first primary coil are nested outside the second portionof the secondary coil; the second portion of the second primary coil isnested inside the second portion of the secondary coil; and at leastparts of the first and third portions of the second primary coil arenested outside the first portion of the secondary coil.
 19. The systemof claim 18, wherein: the first and second portions of the secondprimary coil are coupled together in the first wafer layer by a firstjoiner; and the second and third portions of the second primary coil arecoupled together in the first wafer layer by a second joiner.
 20. Thesystem of claim 19, wherein: the first and second portions of the firstprimary coil are coupled together by a third joiner in the second waferlayer; and the second and third portions of the first primary coil arecoupled together by a fourth joiner in the second wafer layer.
 21. Thesystem of claim 19, wherein: the first and second portions of the firstprimary coil are coupled together by a third joiner in a third waferlayer; and the second and third portions of the first primary coil arecoupled together by a fourth joiner in the third wafer layer.
 22. Thesystem of claim 21, wherein the second wafer layer is above the firstwafer layer, and wherein the third wafer layer is below the first waferlayer.